Q&A - PSLE Math
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pixiedust:
Thank you very much!Let me give it a try :
Jerry bought four times as many pencils as notebooks and spent a total of $21.60. He spent $2.40 more on the notebooks than the pencils. Given that a notebook costs $3.20 more than a pencil. find the cost of a pencil.
spent on pencils = $9.60
spent on notebooks = $12
4U pencils -> $9.60
1U notebook -> $12
1U pencils -> $2.40
$12-$2.4=$9.60
$9.60/$3.20=3
3 notebooks -> $12, each -> $4
cost of each pencil = $0.80
check :
3 notebooks * $4 = $12
12 pencils * $0.80 = $9.60 -
Brenda10:
Catholic High 2011 prim Q16zsqchx:
Please Help!Thanks
Jerry bought four times as many pencils as notebooks and spent a total of $21.60. He spent $2.40 more on the notebooks than the pencils. Given that a notebook costs $3.20 more than a pencil. find the cost of a pencil.
Hi, this quesiton look familar! May I know is from which prelim paper ? -
Need help on this Q :
Mr Samad made some toys to sell. He sold 20% of the toys on Monday. He sold 27 toys on Tuesday. On Wednesday he sold 10% of the remaining toys. After that he found that the toys he had left was 1 more than 1/2 the number of toys he had made. How many toys did he made?
thank you. -
Hi can confirm question 15 of nanyang prelim 2011 answer is 428 2/3 mins or 428 4/7 mins
Thanks -
It should be 428 2/3 mins. This part is tricky, this is the detailed solution my friend gave me.
Vol of tank = 3x3x15 = 13.5 m3 x1000 = 13,500 l
Vol of water = 1/3 x 13.5 =4.5 m3 x1000 = 4500l
13500 – 4500 = 9000 l
2min => water filled = 18x2 = 36l +6l = 42l
9000 / 42 = 214 12/42 = 214 2/7 of 2 min
214x2 =428min , water filled = 42 x 214 =8988 l
9000 – 8988 =12l
1min =18l
12l = 1/18 x12 = 2/3 min
Total time taken = 428 + 2/3 = 428 2/3 min -
:thankyou: smileplease got it
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smileplease:
Hi
Mr Samad made some toys to sell. He sold 20% of the toys on Monday. He sold 27 toys on Tuesday. On Wednesday he sold 10% of the remaining toys. After that he found that the toys he had left was 1 more than 1/2 the number of toys he had made. How many toys did he made?
Mon ------- 2 units
The remaining 8 units is subdivided into 27 (Tues) + 1 part (Wed) + 9 parts left.
8 units – 27 ------ 10 parts -------E1
5 units + 1 ------ 9 parts ------- E2
Multiply E1 by 9 and E2 by 10
72 units – 243 ------ 90 parts
50 units + 10 ------- 90 parts
22 units --------253
1 unit ------- 11.5
10 units ------ 115.
Best wishes
PS ------ The total number of 115 is a whole number which looks logical. However base on this figure, the number of toys sold on Wed is 6.5, which doesn’t seem right. Please check with the source of your question. -
kavisuresh:
may i know anyone has the answer/sol to this?Pls help to solve:
The fig below is made up of a circle, a triangle and two identical semicircles. The diametre of the circle is 8cm and the diametre of the semicircle is 4cm. Find the area of the shaded regions.
http://i54.tinypic.com/11vnyv8.jpg\">
thanks. -
Verysuperkiasu:
Hi
may i know anyone has the answer/sol to this?kavisuresh:
Pls help to solve:
The fig below is made up of a circle, a triangle and two identical semicircles. The diametre of the circle is 8cm and the diametre of the semicircle is 4cm. Find the area of the shaded regions.
http://i54.tinypic.com/11vnyv8.jpg\">
thanks.
This question from SCGS Prelim 2009 looks quite the same as the one shown in the figure.
Please see if it is useful to you.
Best wishes.
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&start=1980 -
Verysuperkiasu:
The big circle + 2 semi circle - the triangle = answer
may i know anyone has the answer/sol to this?kavisuresh:
Pls help to solve:
The fig below is made up of a circle, a triangle and two identical semicircles. The diametre of the circle is 8cm and the diametre of the semicircle is 4cm. Find the area of the shaded regions.
http://i54.tinypic.com/11vnyv8.jpg\">
thanks.
Notice that when the big circle added to the 2 semi circle, the common area between the semicircle and circle is duplicate.